title: Mutational biosynthesis of novel rapamycins by a strain of Streptomyces hygroscopicus NRRL 5491 disrupted in rapL, encoding a putative lysine cyclodeaminase.
abstract: The gene rapL lies within the region of the Streptomyces hygroscopicus chromosome which contains the biosynthetic gene cluster for the immunosuppressant rapamycin. Introduction of a frameshift mutation into rapL by phiC31 phage-mediated gene replacement gave rise to a mutant which did not produce significant amounts of rapamycin. Growth of this rapL mutant on media containing added L-pipecolate restored wild-type levels of rapamycin production, consistent with a proposal that rapL encodes a specific L-lysine cyclodeaminase important for the production of the L-pipecolate precursor. In the presence of added proline derivatives, rapL mutants synthesized novel rapamycin analogs, indicating a relaxed substrate specificity for the enzyme catalyzing pipecolate incorporation into the macrocycle.
authors.affiliation: Cambridge Centre for Molecular Recognition and Department of Biochemistry, University of Cambridge, United Kingdom.
authors.forename: L E
authors.initials: LE
authors.lastname: Khaw
authors.forename: G A
authors.initials: GA
authors.lastname: Böhm
authors.forename: S
authors.initials: S
authors.lastname: Metcalfe
authors.forename: J
authors.initials: J
authors.lastname: Staunton
authors.forename: P F
authors.initials: PF
authors.lastname: Leadlay
mesh_terms: D000642:Ammonia-Lyases / Q000235:genetics*; D002453:Cell Cycle / Q000187:drug effects; D016368:Frameshift Mutation; D008401:Gas Chromatography-Mass Spectrometry; D005798:Genes, Bacterial; D006909:Hydroxyproline / Q000031:analogs & derivatives; D007166:Immunosuppressive Agents / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D009682:Magnetic Resonance Spectroscopy; D005810:Multigene Family; D010875:Pipecolic Acids / Q000378:metabolism; D011090:Polyenes / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D020123:Sirolimus; D013302:Streptomyces / Q000201:enzymology / Q000235:genetics*
chemical_list: D007166:Immunosuppressive Agents; D010875:Pipecolic Acids; D011090:Polyenes; D000642:Ammonia-Lyases; C109507:lysine cyclodeaminase; D006909:Hydroxyproline; D020123:Sirolimus